Pushing up data through the stream in quartz

[Maarten Lankhorst]

I'm trying to figure out how to do this, but I can't find anything on 
the subject.
 From what I can tell, you have to make a media sample, then use 
outputpin_sendsample to deliver it,
so, how do I fill up a media sample with a single frame?
For now, just with NULL data would be sufficient..